Fastener assembly with sealing grommet

Abstract

A threaded fastener assembly which includes a threaded fastener about which is securely disposed an axially movable washer with a resilient grommet fitted thereover. The threaded fastener assembly is adapted to be preassembled within a first apertured work piece such as, for example, a rocker arm cover which is to be mounted upon a second apertured work piece such as, for example, an engine block. The threaded fastener assembly is retainable within the first apertured work piece while holding the fastener in a freely axially movable configuration which permits the fastener to be moved into an elevated position relative to the washer and grommet so as to prevent the fastener from projecting through the bottom surface of the first work piece, thus preventing interference with other surfaces or the second workpieces, and the structure provides seals for preventing fluid from leaking through the apertures of the workpieces.

The invention is claimed as follows: 
     
       1. A fastener assembly adapted for use in connection with at least one apertured work piece for sealing said aperture against fluid flow, said fastener assembly comprising: a fastener;   a washer;   a resilient grommet;   said fastener having a head with a clamping surface thereunder and a shank;   said shank having an upper shank portion, a threaded lower shank portion, and protuberance means spaced a predetermined axial distance from said head between said upper shank portion and said threaded lower shank portion;   said washer including a flange, an axially extending sleeve, and abutment means projecting inwardly of said sleeve; said washer being slidably telescopically associated with said fastener, with an inner dimension of said abutment means being less than an outer dimension of said protuberance means for thereby securing said fastener within said washer;   said at least one workpiece having counterbored recess means defined therein so as to define at least one substantially horizontal sealing surface and at least one substantially vertical sealing surface;   said resilient grommet surrounding and sealingly engaging said washer and including means disposed within and sealingly engageable with said at least one substantially horizontal sealing surface and said at least one substantially vertical sealing surface of said counterbored recess means defined within said at least one work piece so as to seal a first fluid flow path defined between said washer and said aperture of said at least one work piece as a result of axial compression and radial expansion of said grommet means with respect to said at least one substantially horizontal sealing surface and said at least one substantially vertical sealing surface, respectively, of said counterbored recess means defined within said at least one workpiece when said fastener assembly is fully assembled with said at least one workpiece;   said shank and said washer defining a second fluid flow path therebetween; and   means for sealing said second fluid flow path when said fastener assembly is fully assembled with said at least one work piece.   
     
     
       2. A fastener assembly according to claim 1, wherein said grommet includes a sleeve surrounding said washer sleeve, said grommet sleeve including an annular ring integral with an inside surface thereof for retaining said washer in said resilient grommet. 
     
     
       3. A fastener assembly according to claim 1, wherein a body portion of said resilient grommet comprises an outer surface engageable with a surface of said aperture into which said fastener assembly and said body portion are assembled for providing a seal between said surfaces, said body portion further including an annular bore gripping element integrally formed on the outside thereof having an outside dimension slightly larger than or equal to said counterbored recess means for securing and centering said fastener assembly in said aperture of said at least one apertured work piece. 
     
     
       4. A fastener assembly according to claim 1, which includes a band of resilient sealing material around said lower threaded shank portion of said fastener shank for sealing said second fluid flow path. 
     
     
       5. A fastener assembly according to claim 1, wherein said grommet includes a sleeve and said sleeve of said resilient grommet has an annular ring integrally formed about the inside surface of said sleeve for maintaining said fastener in an elevated position in relation to said at least one work piece when said fastener assembly is preassembled in said at least one apertured work piece. 
     
     
       6. A fastener assembly as set forth in claim 1, wherein: said at least one apertured workpiece comprises two workpieces respectively provided with co-axially aligned aperture means.   
     
     
       7. A fastener assembly as set forth in claim 6, further comprising: a band of resilient sealing material disposed around said lower threaded shank portion of said fastener shank for providing a fluid seal for the threaded engagement defined between said lower threaded shank portion of said fastener shank and a threaded portion of said aperture defined within said second workpiece.   
     
     
       8. A fastener assembly as set forth in claim 1, wherein: said grommet comprises a first annular ring portion for engaging said substantially vertical sealing surface of said counterbored recess means, and a second annular ring portion for engaging said substantially horizontal sealing surface of said counterbored recess means of said at least one workpiece, whereby said first and second annular ring portions of said grommet seal said first fluid flow path.   
     
     
       9. A fastener assembly as set forth in claim 1, wherein said grommet further comprises: a second counterbored recess means for receptively housing said flange of said washer; and   an upstanding annular sealing ring engageable with said clamping surface of said fastener head and annularly surrounding said second counterbored recess means and said flange of said washer whereby said engagement of said upstanding annular sealing ring with said clamping surface of said fastener head seals said second fluid flow path.   
     
     
       10. A fastener assembly for connecting a first apertured work piece to a second apertured work piece and for sealing the aperture defined within said first apertured work piece against fluid flow therethrough, comprising: a fastener;   a washer;   a resilient grommet;   said fastener comprising a head, a threaded shank having a threaded portion remote from said fastener head for threadedly engaging a threaded portion of said second apertured work piece, and protuberance means upon said shank and axially spaced from said head;   said washer being axially slidable upon said shank between said head and said protuberance means and being retained upon said shank by said protuberance means;   said first workpiece having counterbored recess means defined therein so as to define at least one substantially horizontal sealing surface and at least one substantially vertical sealing surface;   said resilient grommet including a body portion encircling and mounted upon said washer, said body portion including means for sealingly engaging a surface of said first apertured work piece, and said grommet further including means disposed within and sealingly engaging said at least one substantially horizontal sealing surface and said at least one substantially vertical sealing surface of said counterbored recess means defined within said first apertured workpiece so as to seal a first fluid flow path defined between said washer and said aperture of said first apertured workpiece as a result of axial compression and radial expansion of said resilient grommet means with respect to said at least one substantially horizontal sealing surface and said at least one substantially vertical sealing surface, respectively, of said counterbored recess means defined within said first apertured workpiece when said fastener assembly is fully assembled as a result of said threaded engagement of said threaded portion of said fastener and said threaded portion of said second apertured workpiece;   said shank and said washer defining a second fluid flow path therebetween; and   means for sealing said second fluid flow path defined between said washer and said shank.   
     
     
       11. A fastener assembly as defined in claim 10, wherein said seal means of said grommet body portion comprises an annular rim of said grommet body grommet portion sealingly engageable with said head of said fastener. 
     
     
       12. A fastener assembly as defined in claim 10, wherein said seal means for sealing said second fluid flow path comprises a band of resilient sealing material disposed around said threaded shank of said fastener. 
     
     
       13. A fastener assembly as defined in claim 10, wherein said grommet means disposed within said counterbored recess means comprises an annular flange engageable with a vertical side wall of said counterbore in said first apertured work piece and an annular sealing ring engageable with a bottom horizontal surface of said counterbore. 
     
     
       14. A fastener assembly as defined in claim 10, wherein: said washer comprises an annular flange and a tubular sleeve extending axially from said flange a distance substantially more than a distance defined between said protuberance means and said head of said fastener; and   means projecting radially inwardly from said sleeve of said washer for engagement with said protuberance means of said fastener for retaining said washer and said fastener in assembled relationship.   
     
     
       15. A fastener assembly as defined in claim 14, wherein said grommet includes a tubular sleeve portion extending axially beyond a free end of said washer sleeve portion, said grommet sleeve being engageable with said washer sleeve for initially retaining the grommet and the washer in partially assembled relationship, said washer, when in said partially assembled relationship; supporting said fastener for preventing an entering end of the fastener from projecting beyond said first work piece.